Strange Case of Dr Jekyll and Mr. Hyde is an 1886 Gothic novella by Scottish author Robert Louis Stevenson. It follows Gabriel John Utterson, a London-based legal practitioner who investigates a series of strange occurrences between his old friend Dr. Henry Jekyll and a murderous criminal named Edward Hyde.

Strange Case of Dr Jekyll and Mr. Hyde is one of the most famous pieces of English literature and is considered to be a defining book of the gothic horror genre. The novella has also had a sizable impact on popular culture, with the phrase "Jekyll and Hyde" being used in vernacular to refer to people with an outwardly good but sometimes shockingly evil nature.